We examine the range of Toyota JZ-series six-cylinder engines

By Michael Knowling

One of the most potent engine designs in recent years has come from Toyota
- the JZ-series in-line six. Released as successor to the smooth and
faithful M-series six, the JZ engine has a DOHC 4-valve-per-cylinder head
and comes in 2.5 and 3-litre capacities. You can also find versions with
variable cam timing, a single turbocharger, parallel twin turbos, sequential
twin turbos and direct injection.
There's plenty to discover - so let's dive into the world of Toyota JZ
engines.P>

There’s plenty to discover – so let’s dive into the world of
Toyota JZ engines.

Early 1JZ

The JZ engine range first appeared in 1990 with the naturally
aspirated 1JZ-GE and its twin-turbo 1JZ-GTE cousin.

The 2.5-litre 1JZ uses oversquare bore dimensions (86 x 71.5mm)
and, in naturally aspirated guise, a 10:1 compression ratio. With the aid of a
DOHC, 24-valve head and a dual-stage intake manifold, the atmo 1JZ-GE produces
132kW at 6000 rpm and 235Nm at 4800 rpm. Not bad for a conventional 2.5-litre.

The atmo 1JZ-GE was fitted to the 1990 Japanese-spec Chaser,
Cresta, Crown and Mark II. Like all JZ-series engines, the early 1JZ-GE is
designed for longitudinal mounting and rear-wheel-drive. All of these models
also came with a 4-speed automatic transmission as standard – there was no
manual gearbox option.

Toyota also released a more desirable twin-turbo variant of the
1JZ during 1990.

The 1JZ-GTE twin-turbo was introduced to the Japanese market
Supra GT (JZA70 series), Chaser, Cresta, and Mark II. The 1JZ-GTE employs twin
CT12A turbochargers arranged in parallel and blowing through a front-mount
air-to-air intercooler. With an 8.5:1 static compression ratio, the factory
quoted output is 206kW at 6200 rpm and there’s 363Nm at 4800 rpm. These early
1JZ-GTEs are most commonly available with an auto transmission but a 5-speed
manual version was available in the Supra GT.

In the following year (1991), the 1JZ-GTE was slotted into the
all-new Soarer GT. Output remains at 206kW/363Nm and, again, most examples come
tied to an auto trans. These 1JZ-GTE powered Soarers are quite common on the
Australian market (as ‘grey’ imports).

The early generation 1JZ-GTEs are a great engine from a bang
for buck point of view but be aware that the ceramic wheeled turbochargers are
prone to failure. And they’re costly to fix.

Early 2JZ

The big capacity JZ engine – the 3-litre 2JZ – was introduced
to the Japanese market in 1991. The naturally aspirated version was first seen
in the Crown Royal, Crown Majesta and Aristo saloons while the twin-turbo
variant appeared in the top-of-the-range Aristo.

With its square bore dimensions (86 x 86mm), the naturally
aspirated 1991 2JZ-GE uses a 10:1 compression ratio and a dual-stage manifold to
produce 169kW at 6000 rpm and 284Nm at 4800 rpm. It mightn’t have forced
induction but this is a very strong engine for its capacity.

Curiously, the 2JZ-GE was spread into the Chaser, Cresta and
Mark II range during 1992 but the quoted outputs are down 7kW and 4Nm – we can
only assume there are differences in the exhaust, air intake and perhaps ECU
tune. These early atmo 2JZs are typically fitted with an auto transmission.

The last car to receive the 2JZ-GE was the Toyota Soarer coupe
of 1994. In Soarer spec, the 2JZ generates a full 169kW/284Nm (the same as the
Crown range and Aristo).

And, despite popular opinion, the awesome twin-turbo version of
the 2JZ was not first released in the Supra.

The first application of the twin-turbo 2JZ-GTE was in the nose
of the top-line 1991 Aristo. And, as you’ve probably heard, this is an absolute
humdinger of an engine. With a static compression ratio of 8.5:1 and a
sophisticated sequential twin-turbo arrangement (using a pair of CT12B
turbochargers), you’re looking at a conservatively claimed 206kW at 5600 rpm.
Peak torque is a huge 432Nm at 3600 rpm with 380Nm from just 1300 rpm... In
Aristo spec, the 2JZ-GTE comes fitted with a 4-speed automatic trans.

When the same engine was later installed to the JZA80-series
Supra (from 1993), buyers had the option of a 6-speed manual. Engine output is
identical in the Aristo and Supra.

VVT-i Update

From 1996, the entry-level 2.5-litre 1JZ-GE received VVT-i as
well as a compression ratio increase of 0.5:1. These changes helped achieve a
very creditable 147kW and 255Nm (up 15kW and 20Nm from earlier models). These
VVT-i 1JZ-GEs come fitted to the 1996 Chaser, Cresta, Crown and Mark II; they’re
all autos.

Interestingly, the turbocharged 1JZ came in for a lot more than
just VVT-i and a small compression ratio increase.

For the 1996 model year, the 1JZ-GTE lost its parallel
twin-turbo system in favour of a large capacity single turbocharger. With a big
CT20 turbocharger blowing through an air-to-air intercooler, the VVT-i 1JZ-GTE
produces 206kW (as before) but with a massively improved 378Nm at 2400 rpm. It’s
easy to dismiss the switch from twin turbos to a single turbo as a downgrade but
back-to-back road tests show this to be a far better engine than
previously.

The 1JZ VVT-i single turbo came fitted to the updated Soarer,
Chaser, Cresta and Mark II of ’96. The same engine was then applied to the 1999
Crown and Crown Estate, 2001 Verossa and 2002 Mark II Wagon Blit. Most examples
are fitted with an automatic transmission but there are manual versions to be
found. These engines are quite scarce at the import wreckers but they’re an
excellent package.

The big-banger 2JZ 3-litre also benefited from the introduction
of VVT-i.

In 1995, the Crown and Crown Majesta received variable inlet
cam timing and, like the atmo 1JZ, a slightly higher compression ratio (up to
10.5:1). This went toward achieving 162kW at 5600 rpm and 294Nm at 4000 rpm. The
same engine was then introduced to the Chaser, Cresta and Mark II in 1996 and,
in 1997, a higher tuned version (producing 169kW at 6000 rpm) made its way into
the updated Soarer 3.0GT.

Nineteen ninety-seven also saw the release of the all-new
Aristo (which is recognised in Australia as the Lexus GS300). The new Aristo
boasts the same 169kW output as the updated 2JZ Soarer and comes with tubular
headers and electronic throttle control. Don’t underrate it – this is a very
potent engine considering the absence of forced induction.

Also making news in ’97 was the VVT-i upgrade of the already
stunning 2JZ-GTE sequential twin-turbo. With the introduction of variable inlet
cam timing and electronic throttle control, the 2JZ-GTE’s power output remained
at a conservatively quoted 206kW but torque increased to 451Nm at 3600 rpm –
almost 100Nm more than the ‘awesome’ Nissan R32 Skyline GT-R... This benchmark
engine was available in the ’97 Aristo and ’98 Supra. It was discontinued in
around 2001.

Of course, this engine is always in huge demand in performance
circles and you’ll typically pay top dollar for one.

There were small ongoing changes to the VVT-i 2JZ for the next
couple of years and, most importantly, Toyota released a 158kW/294Nm version in
the Progres sedan and a 162kW/294Nm version in the Altezza wagon.

Direct Injection FSEs

In around 2000, Toyota introduced what are probably the least
recognised members of the JZ engine family – the FSE direct injection variants.
These FSE 1JZ and 2JZ engines are aimed at achieving minimal emissions and fuel
consumption together with no loss of performance.

The 2.5-litre 1JZ-FSE employs the same block as the
conventional 1JZ-GE – everything up top, however, is unique. The ‘D4’ FSE
employs a relatively narrow angle cylinder head with swirl control valves that
serve to improve combustion efficiency. This is necessary to run at extremely
lean air-fuel ratios - around 20 to 40:1 at certain engine load and revs. Not
surprisingly, fuel consumption is reduced by around 20 percent (when tested in
the Japanese 10/15 urban mode). Interestingly, normal unleaded fuel is enough to
cope with the FSE’s 11:1 compression ratio.

The direct injection version of the 1JZ generates 147kW and
250Nm – virtually the same as the conventional VVT-i 1JZ-GE. This highly
efficient engine is fitted to the 2000 Mark II, 2001 Brevis, Progres, Verossa,
Crown and Crown Estate. All are fitted with an automatic transmission.

The 3-litre 2JZ-FSE uses the same direct injection
principle as the smaller 1JZ version but runs an even higher 11.3:1 compression
ratio. This engine matches the conventional VVT-i 2JZ-GE with 162kW and 294Nm.
The 2JZ-FSE is fitted to certain 1999 Crown models and the 2001 Brevis and
Progres. Again, all use automatic transmissions.

These FSE engines are certainly very interesting from a
technical perspective but, at the time of writing, we have not seen one
imported to Australia. On the other hand, the turbocharged 1JZ and 2JZs can be
found in generous numbers – it’s never been cheaper and easier to buy an engine
that’ll run with the giants of the performance world.

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